[U-Boot-Users] PPC8xx chip select configuration at startup

Wolfgang Denk wd at denx.de
Fri Feb 17 21:48:22 CET 2006


In message <43F6091D.7040901 at paulidav.org> you wrote:
>
> So, yes, the first instruction to be executed is located at 0x0 (that's
> how your CPU works), but then the code works using 0x04000000 as a base
> and that is fine. The CPU does not care.

This is not correct. Depending on your HRCW the first instruction  is
either fetched from physical address 0x0100, or 0xFFF00100.

And by the way: that's MPC8xx (not PPC... which traditionally usually
refers to a IBM / AMCC processor).

> > The desired location for FLASH memory will be at 0x0400_0000. This is 
> > the address space to which I link U-Boot.
> >
> That's OK. It will simply limit your SDRAM size to 64M.

And my cause other problems as well. Don't do it. Map flash at a high
address.

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
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